In case of an outer rotor, a cup-shaped rotor yoke is attached to one end part of a rotor shaft, and the rotor shaft is rotatably held by a stator housing. A circular rotor magnet is provided inside of the rotor yoke, and the rotor magnet is set to face pole teeth of a stator core assembled in the stator housing.
To detect rotational positions of the rotor, a position detecting magnet, which is separated from the rotor magnet, is provided to a part of an outer periphery of the rotor yoke. A position of a magnetic pole of the position detecting magnet is detected by a magnetic pole detecting sensor, e.g., Hall element, which is provided on a motor substrate, so that the rotational position of the rotor can be detected (see Patent Document 1).